Genetics, Vol 140, 1175-1186, Copyright © 1995


INVESTIGATIONS

DNA Structures Generated During Recombination Initiated by Mismatch Repair of UV-Irradiated Nonreplicating Phage DNA in Escherichia coli: Requirements for Helicase, Exonucleases, and RecF and RecBCD Functions

W. Y. Feng and J. B. Hays
Department of Agricultural Chemistry, Oregon State University, Corvallis, Oregon 97331

During infection of homoimmune Escherichia coli lysogens (``repressed infections''), undamaged non-replicating {lambda} phage DNA circles undergo very little recombination. Prior UV irradiation of phages dramatically elevates recombinant frequencies, even in bacteria deficient in UvrABC-mediated excision repair. We previously reported that 80-90% of this UvrABC-independent recombination required MutHLS function and unmethylated d(GATC) sites, two hallmarks of methyl-directed mismatch repair. We now find that deficiencies in other mismatch-repair activities--UvrD helicase, exonuclease I, exonuclease VII, RecJ exonuclease--drastically reduce recombination. These effects of exonuclease deficiencies on recombination are greater than previously observed effects on mispair-provoked excision in vitro. This suggests that the exonucleases also play other roles in generation and processing of recombinagenic DNA structures. Even though dsDNA breaks are thought to be highly recombinagenic, 60% of intracellular UV-irradiated phage DNA extracted from bacteria in which recombination is low--UvrD(-), ExoI(-), ExoVII(-), or RecJ(-)--displays (near-)blunt-ended dsDNA ends (RecBCD-sensitive when deproteinized). In contrast, only bacteria showing high recombination (Mut(+) UvrD(+) Exo(+)) generate single-stranded regions in nonreplicating UV-irradiated DNA. Both recF and recB recC mutations strikingly reduce recombination (almost as much as a recF recB recC triple mutation), suggesting critical requirements for both RecF and RecBCD activity. The mismatch repair system may thus process UV-irradiated DNA so as to initiate more than one recombination pathway.


This article has been cited by other articles:


Home page
Proc. Natl. Acad. Sci. USAHome page
M. M. Cox
Historical overview: Searching for replication help in all of the rec places
PNAS, July 17, 2001; 98(15): 8173 - 8180.
[Abstract] [Full Text] [PDF]


Home page
CarcinogenesisHome page
H. Zhang, G. Marra, J. Jiricny, V. M. Maher, and J.J. McCormick
Mismatch repair is required for O6-methylguanine-induced homologous recombination in human fibroblasts
Carcinogenesis, September 1, 2000; 21(9): 1639 - 1646.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
H. Liu, S. R. Hewitt, and J. B. Hays
Antagonism of Ultraviolet-Light Mutagenesis by the Methyl-Directed Mismatch-Repair System of Escherichia coli
Genetics, February 1, 2000; 154(2): 503 - 512.
[Abstract] [Full Text]


Home page
GeneticsHome page
G. A. Cromie, C. B. Millar, K. H. Schmidt, and D. R. F. Leach
Palindromes as Substrates for Multiple Pathways of Recombination in Escherichia coli
Genetics, February 1, 2000; 154(2): 513 - 522.
[Abstract] [Full Text]


Home page
J. Biol. Chem.Home page
H. Wang, C. W. Lawrence, G.-M. Li, and J. B. Hays
Specific Binding of Human MSH2·MSH6 Mismatch-Repair Protein Heterodimers to DNA Incorporating Thymine- or Uracil-containing UV Light Photoproducts Opposite Mismatched Bases
J. Biol. Chem., June 11, 1999; 274(24): 16894 - 16900.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
P. Bertrand, D. X. Tishkoff, N. Filosi, R. Dasgupta, and R. D. Kolodner
Physical interaction between components of DNA mismatch repair and nucleotide excision repair
PNAS, November 24, 1998; 95(24): 14278 - 14283.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
M. Viswanathan and S. T. Lovett
Single-Strand DNA-Specific Exonucleases in Escherichia coli: Roles in Repair and Mutation Avoidance
Genetics, May 1, 1998; 149(1): 7 - 16.
[Abstract] [Full Text] [PDF]


Home page
J. Bacteriol.Home page
R. S. Harris, K. J. Ross, M.-J. Lombardo, and S. M. Rosenberg
Mismatch Repair in Escherichia coli Cells Lacking Single-Strand Exonucleases ExoI, ExoVII, and RecJ
J. Bacteriol., February 15, 1998; 180(4): 989 - 993.
[Abstract] [Full Text]


Home page
GeneticsHome page
R. Friedman-Ohana, I. Karunker, and A. Cohen
Chi-Dependent Intramolecular Recombination in Escherichia coli
Genetics, February 1, 1998; 148(2): 545 - 558.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
D. J. Mazur and F. W. Perrino
Excision of 3' Termini by the Trex1 and TREX2 3'right-arrow5' Exonucleases. CHARACTERIZATION OF THE RECOMBINANT PROTEINS
J. Biol. Chem., May 11, 2001; 276(20): 17022 - 17029.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. Viswanathan, V. Burdett, C. Baitinger, P. Modrich, and S. T. Lovett
Redundant Exonuclease Involvement in Escherichia coli Methyl-directed Mismatch Repair
J. Biol. Chem., August 10, 2001; 276(33): 31053 - 31058.
[Abstract] [Full Text] [PDF]